Continuous casting mold, a shorter side thereof and method of exchanging the shorter side frame

ABSTRACT

A mold shorter side frame of a continuous casting mold is exchanged integrally as it is to enable on-line change of the thickness of the cast piece.  
     As the method, a concave portion for engaging a portion of the moving device and an attaching/detaching mechanism having a fixing jig for fixing the portion of the moving device are disposed at the back of the shorter side frame. Particularly, an attaching/detaching mechanism comprising a concave forming portion having a downwarded opening and a bolt screw passing from the back of the concave forming portion through at least a portion of said portion of the moving device is suitable.

TECHNICAL FIELD

[0001] This invention concerns a continuous casting mold such as forslabs, capable of changing the size of cast pieces and, particularly, itrelates to a movable frame for a shorter side thereof (hereinafterreferred to as a shorter side frame) and a method of exchanging thesame.

BACKGROUND ART

[0002] In recent years, casting molds for use in continuous castingapparatus for cast pieces, particularly, large cast pieces such as slabsare constituted such that the size of the continuously cast slabs can bechanged by displacing the position for each side of a mold duringcasting.

[0003] In the casting mold described above, the frame on the longer sideof a cast piece cross section (longer side frame) is made larger in thewidth than that of the cast piece to be cast. Shorter side frames areput between the longer side frames of large width, and the shorter sideframes are connected to a shorter side frame moving device, for example,a screw type cylinder for changing the width of the cast piece. Theposition of the shorter side frame and, accordingly, the width of thecast piece can be changed by the stroke of the cylinder.

[0004] On the other hand, for the change of the thickness of the castpiece, the size is changed by changing the position for the longer sideframe of the mold and exchanging the shorter side frame with other frameconforming the gap between the longer side frames.

[0005] Heretofore, the moving device and the shorter side frame havebeen fixedly joined by means of a joint or the like. Upon changing thethickness of the cast piece, the mold has been detached entirely and apreviously provided substitute mold in which a shorter frame ofdifferent thickness is set has been disposed to the line. However, thecasting process has to be stopped for a long period of time by suchoperation procedures.

[0006] On the contrary, a technique aimed for simplifying the operationconcerning exchange of the shorter side frame (for the change of thecast piece thickness) of a continuous casting mold includes a continuouscasting mold capable of changing the thickness of the cast piecedisclosed in JP-A-4-224049.

[0007] In this technique, the continuous casting mold capable ofchanging the thickness of the cast piece comprises a longer sidestationary frame and a longer side movable frame capable of opening andclosing by a remote control operation and a pair of shorter side framesput between the longer side frames in which the shorter side framecomprises a fixed shorter side frame connected with a moving device anda variable shorter side frame attached to/detached from the fixedshorter side frame and secured with a shorter side copper plate.Further, a cooling water channel is formed to the variable shorter sideframe constituting the shorter side frame, and the watercharge/discharge channel of the stationary shorter side frame and thewater cooling channel of the variable shorter side frame areengaged/disengaged with each other at the frame mating surface. Further,the mating portion of the stationary shorter side frame and the variableshorter side frame comprises an engaging portion, to facilitate thepositioning by the engaging portion.

[0008] However, in the technique described above of adopting a doublestructure for the shorter side frame, the thickness of the shorter sideframe increases in the moving direction of the shorter side frame andthe moving distance of the shorter side frame for the change of the castpiece width undergoes restriction. Further, since the weight of theshorter side frames inevitably increases compared with a one piececonstitution, load is increased in a case of high speed change of widthduring casting and the large stroke for the change of width can not betaken. For extending the stroke, it is necessary to increase both thelength and the diameter of the moving device for the change of the castpiece width, which results in increased installation cost, operationcost and, maintenance cost, and loss of space.

[0009] A further problem is a danger of water leakage. In the techniquedescribed above, the variable shorter side frame is adapted to beexchanged only for the copper plate section in order to minimize theportion to be exchanged. However, since contact of cooling water withthe copper plate portion in such a structure can be attained only byproviding a cooling water channel between the variable shorter sideframe and the stationary frame, a countermeasure is required for thewater leakage in the joined portion. This requires for example, a presscylinder for pressing the stationary shorter side frame and the variableshorter side frame in order to prevent water leakage from a portionbetween both of them. However, since the continuous casting operationhandles also a powder such as continuous casting powder, obstacles suchas powder tend to intrude to the joined portion between the two frames,which requires utmost care and long time for the joining operation.Further, since the continuous operation time (period) is increased alongwith increasing life of the mold, seal for cooling water at the joinedportion deteriorates sooner. In a case where the water leakage shouldoccur by the failure of the pressing cylinder, intrusion of obstacles ordegradation of the seal, this brings about seizure of the copper plateand, depending on the case, inflow of a great amount of water into themold to possibly cause a worry of steam explosion.

DISCLOSURE OF THE INVENTION

[0010] This invention intends to solve the foregoing problems andprovide a method of exchanging, in-situ the entire shorter side frame,that is, the variable frame corresponding portion (copper plate) and thestationary frame corresponding portion (back frame) integrally withoutdividing them. Further, it intends to provide a shorter side frame withimproved attaching/detaching mechanism relative to the moving device inorder to attain the method, as well as a casting mold using such ashorter side frame.

[0011] In accordance with this invention, the above mentioned object isattained by constituting a connection portion between a shorter sideframe of a continuous casting mold and a moving device for changing thewidth of the shorter side frame (stepping cylinder or the like) with aconcave shape structure and inserting a fixing jig (particularly, afixing jig capable of inserting from the upper end side of the mold)thereby joining to fix the moving device and the shorter side frame.

[0012] That is, this invention provides a continuous casting moldcomprising a pair of longer side frames in which at least one of them ismovable in a forward-to-backward direction, a pair of shorter sideframes put between the pair of longer side frames and movable in theforward-to-backward direction and, a pair of moving devices for movingeach of the shorter side frames in the forward-to-backward directionrespectively in which the shorter side frames and the moving devices formoving the same are engaged respectively by way of one or more ofattaching/detaching mechanisms disposed at the back of the shorter sideframe, the attaching/detaching mechanism has a concave forming portionhaving a concave portion engaging a portion of the moving device, and atleast one of the attaching/detaching mechanisms has a fixing jig forfixing the portion of the moving device to the concave forming portionon every shorter side frame. Referring to the forward-to-backwarddirection, it is defined that the side of the cast piece in each frameis defined as a forward direction and the side on the rear face of theframe is defined as the backward direction.

[0013] In this case, a constitution in which the concave forming portionhas a downwarded opening portion, and the fixing jig is a bolt screwpassing from above through the back of the concave forming portion andat least a portion of the moving device is particularly preferred.Further, it is preferred that the gap of the walls of the concaveforming portion sandwiching a portion of the moving device is madelarger by 0.1 to 0.4 mm (preferably, 0.1 to 0.2 mm) than the size forthe portion of the moving device. Further, it is also preferred that theportion of the moving device fixed to the concave portion of aattaching/detaching mechanism having the fixing jig has a substantiallysquare cylindrical shape (square pin shape).

[0014] Further, in the structure of the attaching/detaching mechanism,the opening of the concave forming portion is directed to the back ofthe shorter side frame, a portion of the lower wall of the concaveforming portion is opened and, further, the fixing jig is a cotterinserted from above.

[0015] In any of the embodiments described above, it is preferred thatthe shorter side frame has cooling water channels at the inside of theintegrated frame.

[0016] Further, this invention provides a shorter side frameconstituting a mold for use in continuous casting, comprising one ormore of attaching/detaching mechanisms to engage a moving device formoving the shorter side frame in a forward-to-backward direction at theback of the shorter side frame, in which the attaching/detachingmechanism has a concave forming portion having a concave portion inengagement with a portion of the moving device and at least one of theattaching/detaching mechanisms has a fixing jig for fixing the portionof the moving device to the concave forming portion. Preferredembodiments for the shorter side frame, the attaching/detachingmechanism and the like are identical with those in the invention for thecasting mold.

[0017] This invention further provides a method of exchanging, in-situ,a pair of engaged shorter side frames (referred to as A) with anotherpair of shorter side frames (referred to as B) in a continuous castingmold having a pair of longer side frames in which at least one of themis movable in a forward-to-backward direction, a pair of shorter sideframes put between the pair of the longer side frames and movable in theforward-to-backward direction and moving devices engaged by way of oneor more of attachment/detachment mechanisms disposed respectively to theshorter side frame for moving the shorter side frames respectively inthe forward-to-backward direction wherein the method comprises, a stepof once stopping casting, a step of moving the shorter side frames A bythe moving devices in the backward direction and stopping the same atpredetermined exchange positions respectively, a step of moving at leastone of the longer side frames to an aimed position in aforward-to-backward direction thereby setting an aimed slab thickness, astep of releasing the attaching/detaching mechanisms for the shorterside frames A respectively to detach the entire shorter side frames Afrom the moving devices by the attaching/detaching mechanismsrespectively, a step of engaging the entire shorter side frames B havinga width corresponding to the aimed slab thickness to the moving devicesby way of the attaching/detaching mechanisms for the shorter side framesB respectively, a step of moving the shorter side frames B by the movingdevices respectively in the forward direction thereby setting apredetermined slab width and a step of starting casting again. Thetiming for the movement of the longer side frame may be set properlydepending, for example, on whether the thickness of the slab is changedin the increasing direction, or in the narrowing direction toward thereducing direction, or the movement may of course be conducted forseveral times.

[0018] In this case, it is preferred that the method further includes,in addition to the step described above, a step of stopping the supplyof cooling water to the shorter side frames A respectively beforedetaching the shorter side frames A from the moving devices, anddetaching the supply pipes for cooling water to the shorter side framesA from the shorter side frames A respectively and further includes astep of connecting the cooling water supply pipes to the shorter sideframes B respectively after engagement of the shorter side frames B tothe moving devices, and starting supply of cooling water to the shorterside frames B respectively.

[0019] According to this invention, in the continuous casting mold, thecopper plate and the back frame of the shorter side frame can beexchanged in-situ easily while leaving them integrally as it is.Accordingly, for changing the thickness of the cast piece, since theshorter side frame can be exchanged on-line in a short period of time,on-line change of the cast piece thickness is possible.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a side elevational view of a first embodiment accordingto this invention.

[0021]FIG. 2 is an enlarged view for an attaching/detaching mechanism inthe first embodiment according to this invention.

[0022]FIG. 3 is a plan view of a first embodiment according to thisinvention.

[0023]FIG. 4 is an explanatory view for the attaching operation of ashorter side ladle in the first embodiment according to this invention.

[0024]FIG. 5 is a detailed view (side elevational view) for pipeinstallation in the first embodiment according to this invention.

[0025]FIG. 6 is a detailed view (cross sectional view as viewed from theback of the shorter side frame) for pipe installation in the firstembodiment according to this invention.

[0026]FIG. 7 is a detailed view (plan view) for pipe installation in thefirst embodiment according to this invention.

[0027]FIG. 8 is a side elevational view of a second embodiment accordingto this invention.

[0028]FIG. 9 is a plan view of the second embodiment according to thisinvention.

[0029]FIG. 10 is an explanatory view for the attaching operation of ashorter side ladle in the second embodiment according to this invention.

[0030]FIG. 11 is a detailed view (side elevational view) for pipeinstallation in the second embodiment according to this invention.

[0031]1 mold

[0032]2 longer side frames

[0033]2 a longer side frame (stationary side)

[0034]2 b longer side frame (movable side)

[0035]3 longer side frame moving device

[0036]4 rod

[0037]5 worm jack

[0038]10, 10 a, 10 b, 10′, l0 a′ shorter side frame

[0039]11 surface of the shorter side frame

[0040]12 rear face of the shorter side frame

[0041]13, 13′ attaching/detaching mechanism (upper side)

[0042]14, 14 a bolt (fixing jig)

[0043]15, 15′ concave forming portion (upper side)

[0044]16, 16′ concave portion (upper side)

[0045]17, 17 b concave forming portion (attaching/detaching mechanism)(lower side)

[0046]18 concave portion (lower side)

[0047]19, 19 a cotter. (fixing jig)

[0048]20 stepping cylinder (upper side)

[0049]21, 21′ rod top end pin (upper side)

[0050]22 rod (upper side)

[0051]23 stepping cylinder (lower side)

[0052]24 rod top end pin (lower side)

[0053]25 rod (lower side)

[0054]26, 26′ moving device

[0055]27 bolt hole

[0056]27 a bolt hole (concave forming portion)

[0057]27 b bolt hole (rod top pin)

[0058]28 mold frame upper end face

[0059]31 mold copper plate

[0060]32 cooling water channel (on the rear side)

[0061]33 cooling water channel (on the side of the copper plate)

[0062]34 mold cooling water supply hose

[0063]35 coupling (for mold cooling water supply)

[0064]36 spray cooling water (Water for cooling cast slab by spraying)supply hose

[0065]37 coupling (for spray cooling water supply)

[0066]38 spray type cooling device

[0067]39 foot roll (support roll)

[0068]41 mold movable cover

[0069]42 mold stationary cover

[0070]43 cooling water channel (for spray cooling water)

[0071]44 mold cooling water discharge hose

[0072]45 coupling (for mold cooling water discharge)

[0073]46 cooling water supply port (for mold cooling water)

[0074]47 cooling water supply port (for spray cooling water)

[0075]48 cooling water discharge port (for mold cooling water)

[0076]50-54 arrow (indicating movement)

[0077]60 water flow (mold cooling water)

[0078]61 water flow (spray cooling water)

[0079]70 opening (for mold cooling water supply)

[0080]71 opening (for mold cooling water discharge)

[0081]72 opening (for spray cooling water supply)

[0082]73 pipe (for supplying mold cooling water to the side of copperplate)

[0083]74 opening portion (for supplying spray cooling water) a moldthickness

BEST MODE FOR PRACTICING THE INVENTION

[0084]FIG. 1 to FIG. 7 show a first preferred embodiment according tothis invention. FIG. 1 is a side elevational view for the firstembodiment, FIG. 2 is an enlarged view for an attaching/detachingmechanism, FIG. 3 is a plan view showing the first embodiment, FIG. 4 isan explanatory view showing the attaching operation thereof and FIG. 5to FIG. 7 are detailed views showing the connection of water coolingpipes

[0085] A continuous casting mold 1 has, for example, as shown in FIG. 3,a pair of longer side frames 2 comprising a stationary side 2 a and amovable side 2 b, which are clamped by way of shorter side frames 10 puttherebetween to form a space of a rectangular cross section, and moltenmetal is poured from a portion thereabove and a slab is drawn downwardlyto conduct continuous casting. The surface 11 of the shorter side frameis defined as a casting side and the rear side 12 is defined as anopposite side. In each of the frames, a copper plate 31 for cooling isdisposed on the side of the cast piece.

[0086] As shown in FIG. 1 to FIG. 3, a moving device 26 has an upperstepping cylinder 20, a rod (upper rod) 22 as a movable part of theupper stepping cylinder 20, an (upper) rod top end pin 21 situated atthe top end of the upper rod 22, a lower stepping cylinder 23, a rod(lower rod) 25 as a movable part of the lower stepping cylinder 23, a(lower) rod top end pin 24 situated at the top end of the lower rod 25.

[0087] In this embodiment, the rod top end pins 21 and 24 correspond toa portion of the moving device (it is not necessarily a top end buthereinafter also referred to as a top end portion of the moving devicefor the simplicity) to be engaged to a concave forming portion of anattaching/detaching mechanism to be described later. In this embodiment,the upper top end pin 21 is made into a substantially square cylindricalshape for the engaging portion with the shorter side frame and into asubstantially circular cylindrical shape for the connection portion withthe rod 22. Further, the lower top end pin is formed into asubstantially circular cylindrical shape.

[0088] During continuous casting, the position for the shorter sideframe 10 can be changed by loosening the clamping for the longer sideframe 2 and advancing or retracting the stepping cylinders 20, 23 tochange the width of the slab.

[0089] On the other hand, the thickness of the slab is changed, forexample, by the following procedures. Referring to an example of FIG. 3,one of the longer side frames (movable side 2 b) is joined by way of arod 4 passing through the other of the frames (stationary side 2 a) to aworm jack 5. The movable side longer frame 2 b moves forward andbackward by a longer frame moving device 3 comprising the worm jack 5and the rod 4 to change the thickness for the cross section of the moldspace. At the same time, the shorter frame 10 is replaced with anothershorter frame of different width. In this invention, exchange of theshorter frame 10 can be conducted on-line in which an upperattaching/detaching mechanism 13 and a concave forming portion (lowerside) 17 constituting the lower attaching/detaching mechanism aredisposed at the back 12 of the shorter frame 10.

[0090] As shown in FIG. 2 in an enlarged scale, the upperattaching/detaching mechanism 13 comprises a concave forming portion 15having a concave portion 16 and a bolt 14 as a fixing jig. The concaveforming portion 15 is attached with the opening being downwarded to theshorter side frame and the concave forming portion has a shape capableof engaging the upper rod top end pin 21 by the concave portion 16.

[0091] The bolt 14 passes through at least a portion of the top end pin21 from the back part (upper) of the concave forming portion 15 along abolt hole 27, thereby fixing the top end pin 21 to the concave formingportion. By the use of the bolt as a fixing jig, an operation spacerequired for the fixing operation by the fixing jig can be madeextremely small.

[0092] The bolt hole 27 a apertured in the concave forming portion 15 ismade somewhat larger than the bolt diameter. A preferred bolt hole sizeis about bolt diameter +0.1 to 0.2 mm. Further, the threadscorresponding to the threads of the bolt are formed only to the bolthole 27 b apertured in the top end pin. The bolt hole 27 b may penetratethe top end pin.

[0093] The concave portion 16 preferably has a substantially identicalshape with that of the pin to be engaged (to such an extent as capableof attaching and detaching). It is preferred in this embodiment todefine such shape and size as forming a gap of 0.1 mm or more in totalbetween the wall of the concave forming portion 15 and the pin 21 whenthey are engaged. This is because powdery matters or the like arescattered and suspended at the periphery of a continuous castingfacility as described above and, unless the gap is disposed, adifficulty may be possibly caused for the attachment/detachment when thepowder should intrude into the concave portion.

[0094] When the gap is excessively large, positioning of the fixing jig(positioning for the bolt hole in this case) is complicated and also ittends to cause rattling. Consequently the upper limit for the gap is setto about 0.4 mm, preferably, about 0.2 mm. Conversely, when the upperlimit of the gap is 0.4 mm or less, centering is facilitated uponinsertion of the bolt 14 through the bolt hole 27 a provided with themargin as described above.

[0095] In this embodiment, it is preferred that the top end portion ofthe moving device fixed by the fixing jig has a substantially squarepin-like cross sectional shape (substantially square cylindrical shape).This is due to the following reasons.

[0096] One of the reasons is that fixing by the bolt screw is morereliable in the case of the square cylindrical shape compared with thecase of the circular cylindrical shape.

[0097] Another reason is that the positioning function is improved. Itis preferred that at least one of the attaching/detaching mechanismsalso has a function of vertical positioning for the shorter frame and itis preferred that the attaching/detaching mechanism having the fixingjig is provided with the function of the vertical positioning (since theportion fixed to the fixing jig is least moveable). For the purpose ofvertical positioning, the contact portion between the concave portionand at least the upper surface of the top end pin is preferably planer.On the other hand, for providing also the function offorward-to-backward positioning (forward-to-backward direction of theshorter frame) with such a shape, it is preferred that the shape isplanar also in the forward-to-backward direction. Accordingly, thesquare cylindrical shape is a most simple shape for satisfying thepreferred conditions described above. Each of the corners for the squarecylinder may be chamfered with no problems.

[0098] In a case of adopting the top end of the generally squarecylindrical shape, since it particularly tends to undergo the undesiredeffect of scattered powder, it is strongly recommended to ensure thegap.

[0099] With a view point of workability, it is preferred to attach a pinof a generally circular cylindrical shape to the top end of the rod and,subsequently, fabricating the engaging portion with the shorter frameinto a generally circular cylindrical shape. Accordingly, the joinedportion with the rod may be of a generally cylindrical shape.

[0100] The lower attaching/detaching mechanism substantially comprisesonly the concaved forming portion 17 (with downwarded opening). In acase of this embodiment using a generally square cylindrical pin as thetop end for engagement with the upper attaching/detaching mechanismhaving the fixing jig, it is preferred that the top end of the lowermoving device is a pin of a generally circular cylindrical shape and theconcave portion 18 is a U-shaped groove (the bottom of the indent has asubstantially semi-circular sectional shape). The constitution describedabove is desirable because in the non-fixed type attaching/detachingmechanism (attaching/detaching mechanism having no fixing jig),positioning (preference being given, particularly, to positioningaccuracy in the forward-to-backward direction) is facilitated and thepositional accuracy in the forward-to-backward direction is notdeteriorated so much when scattered powder or the like is involved.

[0101]FIG. 4 is an explanatory view for the attachment of the shorterframe 10. A shorter frame 10 a shown by an imaginary line is lowered asshown by an arrow 54 such that the lower concave forming portion 17 bsituates between the upper and lower rods 22 and 25 (that is, to aposition not interfering the rods) (10 b). Subsequently, after movingthe shorter side frame 10 b rightwardly as shown by an arrow 50, it ismoved downwardly and the upper and lower moving device top end portions(pins) 21, 24 are engaged with and attached to the upper and the lowerattaching/detaching mechanisms 13, 17 respectively.

[0102] In FIG. 4, an upper end face position 28 for the mold frame isshown for the reference.

[0103] In this case, it is preferred that the rod top end pin 21 of theupper stepping cylinder 20 and the rod top end pin 24 of the lowerstepping cylinder 23 are situated each at a position advanced from thelimit position for the retracting stroke of the stepping cylinder tosuch an extent as capable of ensuring the operationability. In thisembodiment, they were advanced each from the retraction limit by 200 mm.It is preferred that both of the upper and lower pins are stoppedgenerally at an identical position (for the forward-to-backwarddirection of the shorter side frame).

[0104] After engaging the upper and the lower top end portions (top endpins) to respective concave forming portions 15, 17 of the upper and thelower attaching/detaching mechanisms, the bolt 14 a is passed from aboveas shown by an arrow 51 through bolt holes 27 a and 27 b formed to theupper attaching/detaching mechanism and the upper top end portionengaged therewith respectively and the bolt 14 is clamped. The bolt 14may be clamped manually or clamped by using a machine. After attachingthe shorter side frame, a cooling water piping to be described later isconnected optionally to flow a cooling water and then the shorter frameis moved till the casting position (aimed lateral position of slab) inthe forward-to-backward direction of the shorter side frame.

[0105] Upon detaching the shorter side frame, the procedures arereversed. That is, the shorter side frame is moved at first in theforward-to-backward direction to a position suitable to exchange andstopped at that position. Successively, optional cooling water isstopped and the cooling water piping is detached. Subsequently, the boltis loosened and removed and then the shorter side frame may be moved andpulled up in the direction opposite to the arrows 50 and 54.

[0106] Movement of the shorter side frame upon attaching or detaching isnot necessarily restricted to the method described above so long as itcan move with no interference to the longer side frame or the movingdevice (stepping cylinder in this embodiment) and it may also includemovement, for example, in the oblique direction.

[0107] As a matter of course, upon attaching or detaching the shorterside frame, it is necessary that the distance between the longer sideframes is made larger than the thickness a (refer to FIG. 3) of theshorter side frame by the moving device for the longer side frame (wormjack in this embodiment) 3. After the exchanging operation for theshorter side frame, the shorter side frame is sandwiched by apredetermined force by the moving device 3.

[0108] With the structure and procedures described above, the shorterside frame can be integrally attached or detached extremely simply andthe shorter side can be changed on-line.

[0109]FIG. 5 is a side elevational view for showing attachment anddetachment of a cooling water pipes, and FIG. 6 is a cross sectionalview taken along a plane A-A′ as viewed from the back of the shorterside of the frame. Further, FIG. 7 is a plan view taken along a planeB-B′ in FIG. 5 from above. The shorter side frame 10 has a mold copperplate 31 on the surface 11 and has a cooling water channel 33 on theside of the copper plate between the copper plate 31 and the frame mainbody. Further, it also has a rear side water channel 32 for supplyingcooling water to the cooling water channel 33 in the inside of theframe.

[0110] The cooling water channel 33 on the side of the copper plate ispreferably formed as a plurality of grooves to the copper plate as shownin FIG. 7 (in FIG. 6, front elevational view, only the outer edge isshown with no details) but it is not restrictive. The water channels 32at the back are disposed by the number of two in this embodiment but thenumber is not restricted particularly so long as a required water flowrate can be ensured.

[0111] When the shorter side frame is attached, a mold cooling watersupply hose 34 is attached to a mold cooling water supply port 46 by acoupling 35, and a mold cooling water discharge hose 44 is attached to amold cooling water supply port 48 by a coupling 45 thereby connectingcooling pipe. Then, supply of the cooling water is started.

[0112] The supplied cooling water passes through a mold cooling watersupply opening 70 and through the cooling water channels 32 at the backand enters by way of pipe 73 (mold cooling water supply pipe on the sideof the copper plate) in the lower portion of the frame into the coolingwater channels 33 as water flow of mold shown by an arrow 60 in FIG. 5to FIG. 7. Cooling water entering to the copper plate flows upwardly inthe cooling water channels 33 on the side of the copper plate and thendischarged through the mold cooling water discharge opening 71 into thedischarge hose 44.

[0113] On the other hand, when the shorter side frame is detached, afterstopping the supply of cooling water, the coupling 35 for the moldcooling water supply hose 34 is detached from the cooling water supplyport 46 and, in the same manner, the coupling 45 for the mold coolingwater discharge hose 44 is detached from the cooling water supply port48.

[0114] The cooling water supply hose 34 and the discharge hose 44 may beattached or detached manually or mechanically and there is norestriction for the order thereof. Although not illustratedparticularly, the cooling water supply mechanism may be a generalequipment.

[0115] The spray cooling water channel 43 for cooling the lateralsurface of the continuously cast slab may sometimes be disposed to theshorter side frame. Also in this case, the spray cooling water hose 36may be attached or detached by way of the coupling 37 to the spraycooling water supply port 47 in the same manner. The timing forattachment and detachment, as well as supply and stop of cooling watermay be identical with that for cooling water for the frame.

[0116] The stream of the spray cooling water upon connection flowsthrough a spray cooling water supply opening 72 into the water channels(which may also be pipeline) in the shorter side frame and by way of anopening 74 for the spray cooling water spray supply in the lower portionof the shorter side ladle frame to a spray type cooling device 38 asshown by an arrow 61 (spray cooling water flow) in FIG. 5 to FIG. 7.

[0117] As has been described above according to this invention, sincethe cooling water seal for the short side frame is not attached ordetached upon attachment and detachment of the cooling water piping, noparticular consideration is required for the seal leakage upon exchangeof the shorter side frame, and the seal can be always kept intact.Further, the operation for attaching·detaching the cooling water pipingis also simple.

[0118] In FIG. 5, 39 denotes a foot roll (support roll for preventingbulging or the like), which is preferably disposed to the shorter sideframe in view of smooth continuous casting.

[0119] Further, for preventing heat dissipation of molten steel form theupper surface of the mold (prevention of temperature lowering) andpreventing intrusion of obstacles such as powder for continuous casting,a mold stationary cover 42 and a mold movable cover 41 may sometimes bedisposed aside above the shorter side frame, and they sometimesinterfere the carrying space for the exchange of the shorter side frame.In this case, the movable cover 41 may be once detached before theexchange of the shorter side frame and attached again after thecompletion of exchange. It is not usually necessary to detach thestationary cover 42 entirely but the cover plate in the upper portionmay be displaced as required.

[0120]FIG. 8 to FIG. 11 show a second preferred embodiment according tothis invention. FIG. 8 is a side elevational view of the secondembodiment, FIG. 9 is a planer view thereof, FIG. 10 is an explanatoryview showing the attaching operation thereof and FIG. 11 is a detailedview (side elevational view) showing the connection of water coolingpipings.

[0121] Continuous casting mold 1, a pair of longer side frames 2, amoving device 26′ and the like are identical with those in the firstembodiment excepting for the shape of the top end portion (pin) 21′ ofthe upper moving device. Further, also the shorter side frame 10′ isidentical with that of the first embodiment except for the structure ofthe upper attaching/detaching mechanism 13′ (FIG. 8, FIG. 9).

[0122] As can be seen from FIG. 8, in this embodiment, the opening ofthe concave forming portion 15′ in, the attaching/detaching mechanism13′, is directed to the rear face 12 of the shorter side frame 10′, anda portion of the lower wall of the concave forming portion 15′ is openedand, further, the fixing jig is a cotter 19 inserted from above.

[0123] In other words, it may be said that the concave forming portion15′ has a shape comprising a horizontal protrusion, a suspended portionat the top end thereof and a short horizontal turn-back at the lower endof the suspended portion. Further, the shape may also be expressed as adownwardly opened hook, a cramp-shaped configuration with shorter lowerside, or a J-shaped configuration (which may be angled).

[0124] The top end pin 21′ is engaged to the concave portion 16′ at thebottom of the hook. That is, the rod top end pin 21′a is engaged in sucha manner that it is embraced to the inside of the shorter side of thecramp-shaped configuration.

[0125] Then, a cotter 19 is inserted between the rod top end pin 21′engaged to the inside of the shorter lower side of the cramp-shapedconfiguration and the rear face 12 of the shorter side frame 10′ toprevent detachment between the pin and the hook (that is, the pin isfixed to the concave forming portion 15′).

[0126] The cotter is vertically movable, has a taper on the lateralsurface for inserting and detaching from above and it is inserted bybeing enforced downward between the rod top end pin 21′ and the rearface 12 of the shorter side frame 10′, to fix the rod top end pin 21′ tothe concave forming portion 15′.

[0127] It is preferred that the rod top end pin 21′ is of asubstantially circular cylindrical shape in view of the operability ofthe engaging operation but a portion thereof in contact with the cotter19 is preferably formed into a square cross sectional shape so as to bewell fitted with the cotter 19. A handle or attaching tool notillustrated is preferably attached to the cotter 19 so that it isinserted or detached manually.

[0128]FIG. 10 is an explanatory view for the attachment of the shorterside frame 10′. In the same manner as for the first embodiment, afterpositioning such that the lower concave forming portion 17 a situatesbetween the upper and lower rods 22 and 25 (10 a′) (drawing beforelowering is not shown), the shorter frame 10 a′ is moved rightwardly andthen downwardly as shown in arrow 52 and then upper and lower movingdevice top ends (pins) 21′, 24 are engaged with and attached to theupper and the lower attaching/detaching mechanisms 13′, 17 respectively.

[0129] Upon preceding positioning for the top end pin, the rod top endpin 21′ of the upper stepping cylinder 20 is stopped at a positionadvanced slightly from the rod top end pin 24 of the lower steppingcylinder 23 and, when the lower rod top end pin 24 engages the concaveforming portion 17 of the lower attaching/detaching mechanism, the rodtop end pin 21′ of the upper stepping cylinder is retracted. Then, thepin 21′ is embraced inside of the hook-shaped concave forming portion15′. Then, the cotter 19 a is inserted from above as shown by an arrow53. When the inserted cotter 19 is pressed down, fixing between the pinand the hook is completed.

[0130] When the shorter side frame 10′ is detached, the proceduresdescribed above may be reversed. In this case, after removing the cotter19 upwardly, the upper rod top end pin 21′ is advanced slightly by whichthe detaching operation in the upper attaching/detaching mechanismproceeds smoothly.

[0131] Accordingly, also in this embodiment, the shorter side frame canbe attached or detached quite simply, and the shorter side frame can beexchanged on-line.

[0132]FIG. 11 shows attachment and detachment of cooling water pipings.The constitution for each of the portions regarding attachment anddetachment of the cooling water pipings is identical with that of thefirst embodiment and the attaching and detaching procedures are alsoidentical.

[0133] Also in this second embodiment, since the cooling water seal forthe shorter side frame is not detached or attached by attachment anddetachment of the cooling water pipings upon exchange of the shorterside frame, no particular consideration is required upon exchange of theshorter side frame and the seal is always kept intact.

[0134] The two embodiments have been described as above but theinvention is not restricted thereto.

[0135] For example, it is not always necessary to adapt the steppingcylinder as the moving device for the shorter side frame but an ordinaryhydraulic cylinder (positional detection is conducted, for example, by acombination of a guide rod and a positional sensor), a worm jack and ahydraulic motor (positional detection is conducted, for example, by arotation detection device) or a silnuck cylinder can be used. However,the stepping cylinder is particularly preferred since the positioningaccuracy is high. Further, each of the devices described above can beused also as the moving device of the longer side frame and the wormjack is suitable in view of installation and operation space or power.

[0136] Further, while two stepping cylinders consisting of upper andlower stepping cylinder have been adopted as the moving device, thenumber of the moving mechanisms such as the stepping cylinders has noparticular restriction. However, upon change of the slab width duringcontinuous casting, it is preferred to gradually change the thickness byonce tilting the shorter side frame and, for this purpose, it ispreferred that at least two (upper and lower) moving mechanisms areprovided. On the other hand, there is no substantial merit of disposingthem by the number of three or more, the moving device is preferablydisposed by the number of two in view of the cost excepting for a case,for example, where the weight of the shorter side frame is particularlyheavy. Accordingly, it is also preferred that the attaching/detachingmechanisms are disposed at two positions that is upper and lowerposition.

[0137] Upon engagement with two or more moving mechanisms, the fixingjig may be disposed to any of the attaching/detaching mechanisms.However, it is generally preferred to provide the fixing jig to theattaching/detaching mechanism situated to the upper position in view ofthe operability and easy confirmation.

[0138] Further, with a view point of the operability, the fixing jig ispreferably disposed by one to each of the shorter side frames but it maynaturally disposed two or more attaching/detaching mechanisms.

[0139] The attaching/detaching mechanism to which the fixing jig isdisposed may be any mechanism not being restricted to the exampledescribed above. For example, an engaging method of sandwiching themoving device top end (pin) may be used. However, it is preferred to bebased on the shape of the hook which engages the top end since thisfacilitates compatibility between the attaching and detachingoperability and the fixing performance. As a variation for thehook-shaped form, it may be considered a method of forming openings ofthe J-shaped configuration in different upper and lower directionsbetween right and left sides in the second embodiment and moving the pinto the engaging position by the rotation of the rod. However, the firstand the second embodiments are superior in view of the operability.

[0140] For the fixing jig, a key, or a usual wedge, latch or acombination thereof (for example, wedge and bolt) may be considered inaddition to the example described above. It is preferred that the fixingjig of a type to be inserted from above with a view point of theoperability and the confirmation of the fixing state.

[0141] The attaching/detaching mechanism not provided with the fixingjig preferably has a downwarded concave forming portion simply in viewof the operability and the cost, with no particular restriction thereto.For example, attachment and detachment are possible by the mechanismhaving a concave forming portion in the forward-to-backward direction ofthe shorter side frame. However, when the concave forming portion isdisposed in the forward-to-backward direction, since large force exertsin the forward-to-backward direction, for example, in a case of changingthe width of the cast piece during casting, the fixing jig (ofattaching/detaching mechanism with fixing jig) suffers from a burden torequire a strength for the fixing tool. Therefore, the downwardedconcave forming portion is most preferred.

[0142] The top end of the moving device for engagement with theattaching/detaching mechanism is not restricted to the pin as describedabove, but a recess may be formed directly to the rod top end so thatthe attaching/detaching mechanism sandwiches the recess. However, thepin is most preferred in view of easy fixing and strength.

[0143] The shorter side frame may be provided with other auxiliaryfacility useful for the continuous casting operation in addition to thecooling spray or the foot roll described above. For example,thermo-couple that forecast brake-out may be attached to the shorterside frame. In this case, wirings may be disconnected or connected atthe same timing as that for the attachment and detachment of the coolingwater pipings. The foot roll is not restricted only to a single stagebut it may be disposed by plural stages in accordance with the castingspeed or the like.

[0144] Further, the cooling water channels (pipes) in the shorter sideframe are not restricted to the illustrated example but the waterchannels in the copper plate may be of a large width. However, so longas it has been known, the illustrated type is most efficient. Further,supply·discharge ports of mold cooling water may be attached to thelower end part of the shorter side frame (the system are often adaptedso far) but it is preferred to attach them to the upper end part in viewof the operability. Instead of the discharging path for cooling water,discharged water may be supplied, for example, to the spray coolingwater channel.

[0145] For the longer side frame, it is general to make one of themstationary and the other of movable but it is theoretically possible tomake both of them movable. However, the longer side frame is animportant facility to form a path line for the cast piece and it ispreferred to fix one of them in view of the quality control such as forsize and shape since centering is easy upon mold exchange.

[0146] The method according to this invention is suitable to continuouscasting of slabs. While it may be applicable also to cast pieces ofshapes other than the slabs, for example, to bloom billets, but the rolladjustment for the exclusive portion just beneath the mold is difficult.Accordingly, application to the continuous casting of slabs is mosteffective.

[0147] For the size of the slab, a width from 800 to 2500 mm is asuitable range but the range is not restrictive. In addition, a widedegree of freedom exists for the thickness in view of the feature ofthis invention and, for measure use, it is generally from 200 to 300 mm.This invention provides a large merit, particularly, to a continuouscasting facility handling many kinds of thickness.

EXAMPLE

[0148] A shorter side frame and a continuous casting mold in accordancewith the first embodiment (FIGS. 1 to 7) according to this inventionwere applied to a continuous casting line of steel slabs. In this case,the cross sectional size of the slab includes 1800 to 2500 mm width, andthree kinds of thickness of 215 mm, 260 mm and 310 mm. The continuouscasting speed was set to about 1.0 m/min. Each four sets of the shorterside frames were provided on each thickness and the frequency ofexchange for the shorter side frame was about 15 times/month. The gapbetween the top end pin 21 and the concave forming portion 15 was 0.2 mmand bolt fixing/releasing operation was conducted by manual operation.Further, a portion of the upper top end pin 21 in engagement with theconcave forming portion 15 was formed as a square cylindrical shape withabout 50 mm for one side (chamfered) and other portion and the lower topend pin 24 are formed each into a circular cylindrical shape of about 60mm diameter.

[0149] Change of the set thickness in the conventional mold wasconducted by removing the mold main body by hoisting using a crane andsetting a substitute mold again which was previously set with a shorterside frame of another thickness. Therefore, it took for about 90 min forexchange including setting of crane, entire removal of covers, thestand-by time for steam countermeasure upon lifting and the like.

[0150] However, in this embodiment, since, the setting for the thicknesscan be change only by the exchange of the shorter side frame, therequired time is about 30 min or slightly less (about 15 min per oneside) which greatly shortens the time. Further, since steams and thelike are not released because the cover or the like is not detached, anevaluation that the working circumstance was improved has been obtainedfrom operators.

[0151] Industrial Applicability

[0152] According to this invention, since the connection mechanismbetween the shorter side frame and the moving device is formed into aconcave shape structure to adopt a fixing system capable of easyattaching and detaching, the shorter side frame can be exchanged on-lineeasily and in a short period of time, which also make the change of themold thickness in a short time.

[0153] Further, since the shorter side frame has a integral structure,there is no worry at all for the sealing failure for cooling waterbetween the surface and the rear face of the shorter side frame,compared with existent divisional exchange type.

[0154] Further, since the thickness of the shorter side frame can bereduced, this invention can be applied even to a case of modifying theexistent continuous casting mold without narrowing the castable slabwidth.

1. A continuous casting mold comprising: a pair of longer side frames inwhich at least one of the longer side frames is movable in aforward-to-backward direction, a pair of shorter side frames put betweenthe pair of longer side frames and movable in the forward-to-backwarddirection and, a pair of moving devices for moving each of the shorterside frames in the forward-to-backward direction respectively in whichthe shorter side frames and the moving devices for moving the shorterside frames are engaged respectively by way of one or more ofattaching/detaching mechanisms disposed at the back of the shorter sideframe, the attaching/detaching mechanism has a concave forming portionhaving a concave portion engaging a portion of the moving device, and atleast one of the attaching/detaching mechanisms has a fixing jig forfixing the portion of the moving device to the concave forming portionon every shorter side frame.
 2. A continuous casting mold as defined inclaim 1, wherein the concave forming portion has a downwarded openingportion, and the fixing jig is a bolt screw passing from above throughthe back of the concave forming portion and at least a portion of themoving device.
 3. A continuous casting mold as defined in claim 2,wherein the gap of the walls of the concave forming portion sandwichingthe portion of the moving device is made larger by 0.1 to 0.4 mm thanthe size for the portion of the moving device.
 4. A continuous castingmold as defined in claim 2, wherein the portion of the moving devicefixed to the concave portion of a attaching/detaching mechanism havingthe fixing jig has a substantially square cylindrical shape.
 5. Acontinuous casting mold as defined in claim 1, wherein the opening ofthe concave forming portion is directed to the back of the shorter sideframe, a portion of the lower wall of the concave forming portion isopened and, further, the fixing jig is a cotter inserted from above. 6.A continuous casting mold as defined in claim 1, wherein the shorterside frame has cooling water channels at the inside thereof.
 7. Acontinuous casting mold as defined in claim 1, wherein the supply portand/or discharge port of the cooling water channel is disposed to theupper end part of the shorter side frame.
 8. A shorter side frame forconstituting a mold for use in continuous casting, comprising one ormore of attaching/detaching mechanisms to engage a moving device formoving the shorter side frame in a forward-to-backward direction at theback of the shorter side frame, in which the attaching/detachingmechanism has a concave forming portion having a concave portion inengagement with a portion of the moving device and at least one of theattaching/detaching mechanisms has a fixing jig for fixing a portion ofthe moving device to the concave forming portion.
 9. A method ofexchanging, in-situ, a pair of engaged shorter side frames (referred toas A) with another pair of shorter side frames (referred to as B) in acontinuous casting mold having: a pair of longer side frames in which atleast one of the longer side frames is movable in a forward-to-backwarddirection, a pair of shorter side frames put between the pair of thelonger side frames and movable in the forward-to-backward direction andmoving devices engaged by way of one or more of attachment/detachmentmechanisms disposed to the shorter side frames respectively for movingthe shorter side frames in the forward-to-backward direction wherein themethod comprises; a step of once stopping casting, a step of moving theshorter side frames A by the moving devices in the forward-to-backwarddirection and stopping the shorter side frames A at predeterminedexchange positions, respectively, a step of moving at least one of thelonger side frames to an aimed position in a forward-to-backwarddirection thereby setting an aimed slab thickness, a step of releasingthe attaching/detaching mechanisms respectively for the shorter sideframe A to detach the entire shorter side frames A from the movingdevices respectively, a step of engaging the entire shorter side framesB having a width corresponding to the aimed slab thickness to the movingdevices by way of the attaching/detaching mechanisms for the shorterside frames B respectively, a step of moving the shorter side frames Bby the moving devices respectively in the forward-to-backward directionthereby setting a predetermined slab width and a step of startingcasting again.
 10. A method of exchanging the shorter side framesin-situ in a continuous casting mold defined in claim 9, wherein themethod includes a step of stopping the supply of cooling water to theshorter side frames A before detaching the shorter side frames A fromthe moving devices, respectively, and detaching the supply pipes forcooling water to the shorter side frames A from the shorter side framesA respectively and further includes. a step of connecting the coolingwater supply pipes to the shorter side frames B respectively afterengagement of the shorter side frames B to the moving devices, andstarting supply of cooling water to the shorter side frames Brespectively.
 11. A method of changing the thickness of a continuouslycasting slab comprising a step of exchanging the shorter side frames bythe method defined in claim 9.